Fuse with double action.



UNET

JEAN HARLE, or ROUEN, 'FRANCE r FUSE wrrn DOUBLE norton.'I

Specification. of Letters Patent.

Patented July 13,1909.

Application filed February 4, 1908. Serial No. 414,281.

To zZZwhom it may concern:

Be 1t known that I, J EAN HARL, a citizen of the French Republic, andresident of Rouen, France, havev invented new and use? fuses chargedwith black powder, the speed of combustlon of which does not exceedseveral centimenters per second slow fuses Bicki ford. 2.-The quickfuses also charged with black powder, but having a speed of combustionattaining several hundreds ofmeters per second (instantaneous fusesBickford. 3.--The detonating tubes which are charged with anA explosive,the detonating speed of which attains several kilometers per second.

' It is evident that a detonating tube or fuse, which according to themanner in which it is ignited, belongs either to the rst category or tothe third one, that is to say, which, at will, can consume slowly andserve as a fuse, or detonate instantaneously and serve as detonatingtube, would render great services, particularly for military purposes,where it 1s important to reduce the number of fuses in service. Therehave already been made numerous trials in this respect, all experimentshaving however been directed to the search of a special explosive,adapted to consume slowly or to detonate, according to' how it isignited. There have been produced particularly tubes filled withfulminate of mercury but these experiments have never given asatisfactory result. The fuses obtained either consume too quickly ortoo irregularly; further, they are too sensitive with regard tomechanical actions, so that their use necessitates precautions which areinadmissible for practical use. Onehas tried to diminish thesensitiveness of thefulminate of mercury by phlegmatizing the same, butthen the fuses can act only as detonating tubes, belonging to the thirdcategory. Further, the experiments made for chlorated ex losives havenot given satisfactory resu ts.

The object of the present invention .is a fuse at double action, whichentirely fulfils all the practical requirements. This fuse 1scharacterized by the fact that instead of being filled with a singleexplosive, it coiitains two explosive charges, one of which, thegunpowder, insures slow action, while the other, which is an explosive,secures the instantaneous detonation. In principle there are juxtaposeda fuse of the first category and a detonating tube of the thirdcategory; but the difficulty consisted in securing the regularity andthe security of the two modes of operation, without increasing thediameter of the fuse over the usual diameter of fuses and detonatingtubes, sa 5 mm., 5 maximum; on the other han there had to be avoided anyreaction of the one explosive upon the other and particularly to beprevented that theheat, produced by the combustion of the gun-powder,provoked the detonation of the explosive.

The fuse accordingl to the present invention fulfils allth'esccondit-ions; it is represented, by way of example, in theaccompanying' drawings. t

Figure l is a longitudinal section through the fuse; Fig. 2 isga crosssection through the same; l4`igs.v3 tb (i represent how, with this fuse,branchings ofi' and priming can be effected. Fig. 7 is a verticalsection of Fig. G and Fig. 8 represents in 'longitudinal section adouble clamp. 4

This fuse essentially consists of a detonat= ing tube which forms thecentral core and is composed of a lead-sheath a and a filling b astrinitrotolucne, trinitrobenzene, trinitrophenic acid etc. To insure theoperation of such a fuse, the explosive core must have a diameter of atleast l mm. and the sheath must be without fissures. .This detonatingtube is extremely fiexible, like a wire, and, for obtaining the novelfuse, it is only necessary to replace the central Wire which isfrequently used .in the manufacture ofthe slow Bickford fuses, by thesaid detonating tube. Vith some care, the gun-powder o is easily drawnalon'g with said central detonating tube and forms a regular layerbetween said tube and the outer plaited sheath d, and there can be madefuses a hundred meters long without provoking -a rupture of the' tube a.The fuse thus obtained looks exactly like the ordinary fuses, butcontains an explosive central core b and an annular layer c' ofgun-powder, the two exploslves being separated the one from the other bythe lead tube a. v

This fuse is of great flexibility and 'at the same time of greatresistance. The detonating tube a is protected by the plaited cover'dand by the layer of powder c so that -it =is elim-,tively protectedagainst accidents during its manipulation and transport. Itsoperativeness is always assured. As regards the slow fuse proper, itdoes not greatly di tler from the ordinary Biektord fuses, and

its action is in every pointsimilar to the action of said fuses.

'lhe security of these fuses at double action is absolute; thedetonation cannot be eifel-ted by violent shocks or blows throughemu-getic friction, nor through infiammation. 'ihe dangers are notgreater than-those of an ordinary lickiord Jf'use containing nothing butblack powder.

lt is to be understood that the central core l) ean belinade fromdifferent explosives; the one which has given the best results is a.tube lilled with trinitrotuluene, the leadsheath a, of which had 2 mm.of diameter. The finished fuse was of a diameter of 5 nim. and weighed40 gr. per meter. The speed ot combustion through simple ignition wasot' about one centimeter per second. The fuse burned regularly and thetrinitrotoluene burned without influencing the combustion of the blackpowder. rlhe detonating speed obtained by exciting the tube by means ofa detonator of fulininate of mercury, was 4400 meters per second. Onehas detonated tubes which were longer than 100 meters, without.

any interruption of detonation and there has not, been ,traced anyresidue of the black powder, said gun powder being completely destroyedthrough the detonation of the t r nitrotoluene.

W'ith this fuse at double action branchinffs oli' can be made by simplytying each branchfuse against the main-fuse after the branchA lfuse hasbeen provided with a detonator of fulminate 'of mercury.

Fig. 3 re resents a main-fuse e to Which, by means o a thread f, the endof a branchfuse c is tied which previously has been provided with adetonator g. i

Figs. 4 and 45 represent a s ecial joint which permits to dispense withtlie thread f. r1 his joint is made from sheet iron and consists of aclamping late h which has a spring like action an which receives rst themain fuse e whereu on the detonator e fixed at the end of the ranch fusee1 is ns'erted in one end of the plate. The detonator g is securelypressed against the fuse a through the spring like action of clamp h. Toobtain several branchings otf, from the same point of the main fuse,this main fuso is cut oit' at this point, as shown in Figs. G and 7, itsend is covered with a detonator z' and several detonators 11, g2, g3, g4are tied against said detonator z' each of which covers the end of abranch fuse el, e2, e3, e4.'

Finally, to facilitate the initial priming of a fuse according to thepresent invention, with the View of detonating the same, a double clampis used, such as shown in Fig. 8, whichis composed of a central part L,the inner diameter of which is equal to the outer diameter of theprimers of fulminate of mercury, while at each ot' its end this centralpart is prolongated by thecurved prolongations Z which are kept openthrough their elasticity, but can be closed by means of the rings m. Ifthis apparatus is to be used, the end of the fuse ois covered with adetonator 'n which is inserted to about the middle of part 71.; then thering m is moved so that the fuse is securely maintained in its position;the primer p, which covers the end of the fuse Q serving as primer, isthen insei-ted into part It from the other end until it touches thedetonator a. Fuse g is then secured in its position by the correspondingring lm, bein moved. Under these conditions, whcn Iuse g is ignitedwhich acts as slow fuse, it Will provoke the detonation of fuse o actingas detonating tube. (.)ne has to be careful, that the arms l of theclamp be short enough so that they only come in contact with the metalsheath of the detonators and not with the fuses o andl This prim-- ingarrangement can be exposed for a very long time to any weather withoutlosing its operativeness. In certain cases, the detonator n can evenbedispensed with and the fuse o can be directly placed against thedetlonator n.

